Bringing Putin to book

Ukrainian President Volodymyr Zelensky signed an agreement with CoE secretary general, Alain Berset, on 25 June, setting up the special tribunal. Subject to it securing the necessary political backing and budget, the tribunal will be established within the framework of the CoE, which is not part of the European Union.

Work on the first phase of the court could progress in 2026. In his speech to the Council of Europe parliamentary assembly in Strasbourg, Zelensky was cautious in his optimism but stressed that the agreement was “just the beginning”.

“It will take strong political and legal cooperation to make sure every Russian war criminal faces justice — including Putin,” he said. He knows, through years of hard experience as he travelled the world seeking help from Ukraine’s allies, that political support can be fleeting.

Inspired by ad hoc courts established after major conflicts such as the Nuremberg tribunal after the Second World War or, more recently, the International Criminal Tribunal for the former Yugoslavia (ICTY) in the 1990s, the Ukraine tribunal has been established with the aim of holding to account the perpetrators of the first full-scale armed conflict in Europe in the 21st century.

The prohibition against the crime of aggression is a basic principle of international law, and a key part of the UN charter.

In principle, the crime of aggression should be prosecuted by the International Criminal Court (ICC). But as Russia is not a party to the Rome Statute which underpins the court, that option was ruled out. Similarly, Russia’s veto on the UN Security Council meant that it would be impossible in practice to set up a court under the mandate of the UN — as the ICTY was in 1993.

The Ukraine special tribunal, which was developed by a Core Group, made up of states plus the EU and the Council of Europe, seeks to fill an obvious accountability gap. If the illegal invasion is left unpunished, it would set a dangerous precedent.

Such impunity would embolden Russia and inspire others with revanchist ambitions, undermining an already shaky international order. The US, which was instrumental in setting up the Core Group under the presidency of Joe Biden, withdrew in March 2025 when Donald Trump took office.

The statute of the special tribunal sets out that the court will be based on Ukrainian law and will have a strong link to the country’s legal system. Ukraine’s Prosecutor General will play a key role in the proceedings, referring evidence for further investigation by the tribunal. But it will be internationally funded with international judges and prosecutors, and strong cooperation with the International Criminal Court. It is likely to be based in The Hague, although this has yet to be confirmed.

The need for accountability for the illegal invasion of Ukraine was stressed in a resolution of the UN General Assembly in February 2023 as the war headed into its second year. The resolution, which calls for “appropriate, fair and independent investigations and prosecutions at the national or international level” to “ensure justice for all victims and the prevention of future crimes” was approved by an overwhelming majority of 141 states. Any country in the world can join this core group to support its establishment.

Unlike previous international courts, the caseload is likely to be extremely narrow. There are likely to be dozens of charges, rather than hundreds or thousands, which is perhaps reassuring in terms of managing costs.

The tribunal will focus on those “most responsible” including the so-called “troika”: Vladimir Putin, Prime Minister Mikhail Mishustin and Foreign Minister Sergey Lavrov. Charges may also be levelled against the leadership of Belarus and North Korea for their role in aiding, abetting and actively participating in the war of aggression. But don’t expect Kim Jong Un or Alexander Lukashenko in the dock anytime soon.

The court has opted for a novel approach to a longstanding customary rule by noting that heads of state are not functionally immune from prosecution. But it adds that indictments won’t be confirmed until such time as the suspect is no longer in office.

Trials can take place in absentia if the accused fails to attend and all reasonable steps taken to apprehend them have failed. But, like the ICC, the court will still rely on states to apprehend and physically transfer indicted individuals in due course. This will inevitably limit the chances of seeing any of the key individuals actually in a court, something that has also dogged the ICC.

The fact that a tribunal has now been set up is a major development in international criminal justice. But it is now in a sort of purgatory, existing and not existing at the same time. To become operational, another treaty known as an enlarged partial agreement must be signed by interested states. This will have to be ratified by many national parliaments, depending on their constitutions. This process could take years.

But simply by creating the framework for the tribunal, the Council of Europe has demonstrated its commitment to ensuring accountability. In a further development, the European Court of Human Rights delivers its long-awaited judgment in the case of Ukraine and the Netherlands v Russia on 9July.

This concerns “complaints about the conflict in eastern Ukraine involving pro-Russian separatists which began in 2014, including the downing of Malaysia Airlines flight MH17, and the Russian military operations in Ukraine since 2022”. The judgement will add further momentum to these accountability efforts.

Symbolic as it may seem, last week’s agreement creates a real opportunity for the international community to send a message that impunity for international aggression is intolerable — not just for the victims, but for all who believe in the rule of law.